An easy fish to like, tilapia is inexpensive and widely available, and its mild flavor offers creative cooks a blank canvas for experimentation. One of its few downsides is that it's hard to recognize when those pale fillets are past their prime.
A spoiled piece of tilapia won't change color the way red meat does, so you'll need to rely on other sensory cues.
- Touch the fish with your fingers. If your fingertips feel sticky afterwards, that's a bad thing.
- Check the packaging for thick fluid oozing around the fillet.
- Smell the fillet. If it has funky, "fishy" odors, it's not fresh.
All of these symptoms are caused by bacterial activity, so they're sure signs of spoilage. If you detect any of them on the tilapia, err on the side of caution and throw it out.
Spoilage vs. Food Safety
A larger problem is that spoilage and food safety are not exactly the same thing. Your senses can tell you when a fillet of tilapia is spoiled. Pathogens -- potentially harmful bacteria, viruses and parasites -- are usually undetectable. Good food-handling practices are your only real defense against those. Clean your hands and utensils scrupulously before and after handling raw fish, and never expose tilapia to contamination from meats, poultry or other fish.
Bring it home from the store in a cooler, if possible, and refrigerate or cook it immediately. A piece of tilapia that spends two hours at room temperature -- or even one, on a hot day -- should be discarded.
Storage Time Guidelines
Your calendar provides another way to check whether tilapia is still good. Fresh fish must be eaten within 48 hours at most, so if it's been in the refrigerator for two days, you should discard it. If the tilapia came packaged from the supermarket, count from the packaging date. If it's dated from the day before, you should cook it on the day it's purchased. That's a good rule in any case, because fresh fish is so perishable.